How To Investigate Serial Murder

Active serial murder investigations present many challenges to law enforcement, according to the FBI. Some of the pressures include public outcry, the media, law enforcement management, and the frustration of investigators at not being able to identify the suspect. In the vast majority of male serial killer cases, there is no identifiable relationship between the suspect and the victims. Female serial killers are a different breed entirely, which we’ll delve into more deeply in future post.

For this post, when I say “serial killer” or “offender” I’m talking about men who murder three or more people with a cooling off period (apparently, the new definition of serial killer is someone who murders two or more people, but I haven’t found a logical reason for lowering the bar).

With most violent criminal investigations, a recognizable connection emerges between the killer and his victim. Which is why investigators first look at victimology and the people closest to them: spouses, lovers, friends, acquaintances, business partners, and rivals. When investigating serial murder, however, the normal link is often missing.

Crime Scene Analysis

As Adam from Writers’ Detective explained in a past blog post, the murder investigation begins with the crime scene. Investigators look at the interaction between the offender and victim…

• Approach to the victim. Meaning, how did the killer capture the victim? Did he force entry? Was the victim abducted from a different locale? Did he talk his way into the house? Or ambush the victim in a dark parking lot?
• Nature of physical interaction. For example, did he beat the suspect in a rage-fueled frenzy?
• Was there any sexual interaction? And if so, what’s the nature of it?
• Choice of weapon(s). The type of weapon used tells investigators a lot about the suspect. Strangulation, for example, can indicate a killer wants to feel his victim die, which also indicates he might fall under the classification of a power-control killer or sexual sadist, if sex is involved.
• Manner of death. Investigators first need to consider whether the death is natural, accidental, suicide, homicide, or undetermined (the coroner or Medical Examiner makes the final determination).
• Method of body disposal. What did the suspect do to the victim postmortem? Did he pose the victim? Bury her in a shallow grave? Only cover the face? Which might indicate an association.

All these factors help determine if the murderer has killed before, as well as his level of skill.

Victimology

Along with victim/offender interaction, the victims’ risk factors are another key element in investigating serial murder. The victims’ risk levels can be defined by their behavior, lifestyle, personality, habits, physical attributes, location, circumstances, judgment, security consciousness and/or other personal factors.

Victimology information includes:

• Gender
• Age
• Occupation
• Marital status
• Former intimate relationships
• Prior arrest history
• Drug and/or alcohol use or abuse
• Type of residence
• Neighborhood dynamics
• Community crime rate

Victims are classified from low to high risk. A low risk victim is someone who has a minimal probability of being targeted. A moderate risk victim is someone with a minimal probability but due to behavior at the time of victimization, she became more at risk. A high risk victim is someone who has a high probability of being targeted. Examples: prostitutes, drug addicts, or the homeless.

Victimology leads to how the offender is choosing his victims.

Which usually falls into three areas:

• Availability: Offender’s access to victims.
• Vulnerability: Situations and circumstances in victims’ lives that allow them to be victimized (this wording may sound like the FBI is blaming the victim, but they’re not. Look at Vulnerability as another tool in the catch-the-serial-killer arsenal).
• Desirability: The attractiveness viewed in potential victims (sexual murders). Take, for instance, Ted Bundy, who mostly targeted women with long brown hair parted down the middle (lookalikes of his ex-girlfriend). Or perhaps, the victim fills another need of the offender (Mommy issues, for example).

Utilizing crime scene analysis with victimology can reveal if the offender targeted specific victims, or some unlucky person who wandered into their hunting area — aka “victim of opportunity.” A hunting area is a place where the offender feels most comfortable, or a place they identify with in some way. A certain neighborhood near their work, home, frequent vacation spot, military base, etc. Also known as their comfort zone.

Motivation

Motivation is determined by examining a few different elements:

• victim/offender interaction;
• choice of victim;
• forensic evidence.

Serial killers who share motivations may also share similar traits. Makes sense, right? Here’s the wrinkle to that argument. The specific factors, or combination of factors, differ from killer to killer due to the uniqueness of the individual. To properly analyze the killer, investigators need to look at the full picture: choice of victims, means of killing, and the proclivities of the killer.

Case Linkage

Case linkage is key to identifying a serial killer. Do other murders, even ones in other jurisdictions, share the same MO? It’s also crucial to identify the first murder (or attempted murder) in a series. The first murder has the greatest risk of illuminating the killer’s mistakes, and these errors assist in identifying a suspect.

Case linkage is based upon the following criteria …

• Consistent MO;
• Similar types of victims;
• A similar approach to victims;
• Similar physical and/or sexual interactions;
• Use of similar weapons;
• Causes of death show similarities;
• Forensic results;
• Geographic locations of murders;
• Other aspects include the time of day/night, day of the week, and/or time of year. In RACKED, for example, the Serial Predator only strikes on Thursdays. Why? You’ll have to read the book to find out. 😉 More on that later …

Investigation

Searching for a serial killer requires investigators to view the investigation as a summary.

Geographic: Is the serial killer operating in a rural, suburban, or inner city area? Does the offender’s choice of victims limit the reach of potential victims? Is the area predominately one race or racially mixed? Geographic results can indicate the race of the offender, as he can easily blend into the fabric of society.

Victim Type: Is he targeting specific individuals within a hunting area, or are any potential victims that enter “the zone” deemed fair game? Do other factors contribute to targeting these specific victims? Prostitution, for example.

Means of accessing victims: How does the offender come in contact with the victims? Does he enter a residence? Is he picking up a prostitute on the street? Is he utilizing other circumstances? To use Bundy as the example again, he slid his arm into a fake cast or sling and then asked a potential victim for help. In fact, he lured two separate women from the same beach, on the same day, with that ruse.

The answers to these questions will showcase the strengths and weaknesses of the serial killer’s abilities.

Use of weapons and/or manner in which he kills: Does the serial offender choose a weapon that he’s experienced with using? Does the manner in which he kills highlight past experiences? All of these factors can reveal if the serial killer has certain background characteristics.

Interactions with victims: Do the physical and/or sexual interactions with the victims align with any previous experience? Certain distinct behaviors may indicate the offender has committed other types of crimes. Example: molestation, rape, stalking, assault, torture, etc.

Body disposal location/manner: Where the serial killer chooses to dump the bodies may reflect his familiarity with the area. Also, the way he disposes of the body reflects the nature of the relationship between killer and victim. Example: if only one of the victims had the bones of her face shattered, then that might indicate a prior relationship with the killer. Even without cognizant awareness, the killer may be trying to erase her identity, thereby satisfying a deep-seeded thirst for revenge.
Because body disposal scenarios reveal crime characteristics and offender characteristics, the manner of body disposal is one of the central factors in solving serial murder.

The key to identifying potential suspect pools originates with correctly identifying the dynamics involved in a serial murder case. Investigators must look at a collation of different factors …

• MO
• Forensics
• Offender/victim interaction
• Motivation
• Victim selection
• Victim targeting area
• Victimology

We all have different experiences which help mold us into the people we are today. It’s no different with serial killers. Each individual offender exhibits unique violent interactions. All of these factors need to be identified and considered. The investigator can’t plug one or two factors into a template and expect to zero in on a single suspect. Rather, these checklists measure offender behaviors that result in a pool (or several pools) of potential suspects.

Sounds tedious, right? The biggest issue facing investigators is sorting through mountains of information in serial murder investigations, combined with identifying a specific individual within pools of potential suspects. Most investigators don’t have a lot of experience with serial murder. Hence why FBI’s National Center for the Analysis of Violent Crime is uniquely qualified to provide investigative and behavioral assistance. 

Segway #ShamelessPlug

You know who does have experience with serial murder? Sheriff Niko Quintano from the Grafton County Series. In RACKED, he’s hot on the trail of the Serial Predator, thanks to his wife, Crime Writer Sage Quintano, who first uncovers a connection between abductions.

It starts with an innocent stuffed animal. It ends in mind-numbing terror.

Five missing boys and an adult corpse found in the town’s water shed was only the beginning for Sage and Niko Quintano. After a hooded-stranger gives their son, Noah, a stuffed animal—the exact Christmas moose given to all the missing boys days before their abductions—their lives spiral downward into uncertainty.

Could Noah be the next boy to go missing?

As they piece together each cryptic clue, the future looks more and more grim. But what they soon discover blows everyone’s mind, the truth teetering on the unfathomable.

What does it all mean, and where do they go from here?

Pre-order RACKED for 99c

Releases Aug. 7th, 2019. Want a sneak peek? Read the Opening Chapter.